Premium Monometal Bullet gets a Facelift

With its improved ballistic coefficient and Heat Shield Tip, Hornady’s new expanding copper CX is an upgrade on the old GMX.

I am actually old enough to remember reading the early advertisements for, and reviews of, Randy Brooks’ Barnes X bullet – a lead-free hollow point that was heralded for its high weight retention and
deep penetration. At the time, these newfangled projectiles were only available in component form, and it took a few years before I had the time, money and space to begin to experiment with them. Explaining the concept of a bullet without lead to my dad was no easy feat, and I completely lost him once we put those bullets on paper. It seemed, at least with those initial Barnes X bullets, that a rifle would either love them and put them into tiny little groups, or hate them (as all of my rifles did).
Three decades have passed since the Barnes X was released. Many improvements have been made, and now nearly every major manufacturer of projectiles offers some sort of copper alloy bullet in their lineup. Hornady – an industry name dating back to the post-World War II era of bullet making – had their GMX (Gilding Metal eXpanding), which featured their signature red polymer tip atop a copper-alloy hollow point boattail.

JUST AS THE ELD-X and ELD Match bullets benefitted from the upgrade, so has the CX, improving the downrange performance by providing a more consistent ballistic coe cient. But that is not the only function of the Heat Shield Tip. Because the copper alloy used in the CX is harder than lead, the hollowpoint will certainly appreciate a bit of help to open upon impacting the game animal. So the secondary purpose of the polymer tip is to act as a wedge, driving the walls of the hollow point open upon impact. Whereas the original Barnes X design has no polymer tip, among other issues was that consistent expansion was guaranteed, and many times the bullet would simply whistle through a game animal much like an arrow with a field point.
The early copper alloy bullets –with a solid shank – also generated a whole bunch of copper fouling in the bore of a rifle; I spent hours with an ammonia-based cleaning agent and a nylon brush (once I learned what the solvent would do to a bronze brush) scrubbing the bore. Cutting grooves in the shank of the bullet served to reduce both copper fouling and interior pressures, but Hornady soon found that the geometry of the groove and its associated transitions onto the shank also play a role in BC, and therefore the downrange performance. Hornady’s revised groove geometry on the CX bullet is another of those features that may seem inconsequential, but if a longer shot is all you’re offered on the hunt of a lifetime, I’d want all the advantages I could get.

The GMX was a very consistent bullet, delivering fine accuracy with devastating terminal performance. And like so many of the monometal bullets, these would retain over 90 percent of their original weight, if you could recover them at all. In my experience, it was di cult to get a GMX to stay inside of a game animal, especially on a broadside shot. I write about the GMX bullet in the past tense, because –as good as the design is – Hornady has discontinued its production. Shooters are saddened when a bullet is discontinued, especially when that bullet gives the performance that they can rely on year after year. But Hornady has never been a company to sit idly by when a product can be improved, and their engineers recognize where an improvement can be made. New for 2022, Hornady introduced the CX (Copper alloy eXpanding) monometal softpoint.
If you were paying attention when Hornady released the ELD Match and ELD-X bullets, extensive testing revealed that the conventional polymer tips used in most projectiles would actually deform, or melt, due to the heat generated by atmospheric drag. This would negatively affect the bullet’s ballistic co-efficient, reducing the retained velocity and energy downrange. The result of the attempts to create a heat-proof tip is their Heat Shield polymer tip.

THE HORNADY CX is assuredly a hunting bullet, and copper alloy projectiles can be a contentious topic among hunters. Like any (relatively) new technology, the traditionalists will be slow to warm to any product that deviates from that which they hold dear. To many people – my dad included – a hunting bullet has a copper jacket and lead core, and anything else is silliness. But with the current trend of frowning upon lead projectiles, some states have passed legislation banning the use of lead core projectiles. California has been at the forefront of this movement, insisting that the lead fragments left behind in the gut piles of hunted animals are a potential health hazard for condors and other scavengers. And of late, my native New York has heard rumblings of a lead ammunition ban on the hundreds of thousands of acres of state land available to hunters. But make no mistake, the copper alloy bullet is the projectile of the future, so it might warrant a few notes about its properties and performance.

The copper alloy used in the construction of these bullets is less dense than lead, so with the caliber
being consistent, a copper alloy bullet of a particular weight will be longer than one of lead core/
copper jacket construction of the same weight. The classic cartridges we have come to know and love are most often equipped with a twist rate best suited to cup-and-core bullets, so to function properly with those twist rates, you may see copper bullets top out at lighter weights. For example, the common twist rate for the 6.5 Creedmoor (and other 6.5mm cartridges) is 1:8; while that twist rate can stabilize cup-and-core bullets as heavy as 160 grains, in a copper alloy bullet, about 130 grains is all that will function properly. For the hunter, it’s not the end of the world, as the high weight retention of the lighter bullet will make up for the lack of weight.
Just be aware of the difference when looking at bullet weights for your favorite cartridge. The structural integrity of the bullet will withstand high impact velocities, so unlike some of the cup-and-core bullets, there is nothing to separate, and the CX make a sound choice for magnum cartridges.

HORNADY OFFERS THE CX bullet in both component form and in loaded ammunition as part of their Outfitter ammo line. I have used both, and I have found the bullet to be among the best available.
In component form, I’ve had good results with the .277-inch 130-grain CX in the .270 Winchester and 6.8 Western; the 150-grain 7mm CX in the 7mm PRC and .280 Ackley Improved; and the 165-grain .308-inch diameter CX in my .300 Winchester Magnum. In the Outfitter ammo line – loaded in nickel cases with sealed primers to battle the most inclement weather – the 6.5 Creedmoor 120-grain CX load printed very nice groups, as did the new 7mm PRC, loaded with the 160-grain CX bullet. I got to see the results of the latter when a hunting buddy cleanly took a bull moose in British Columbia with the new cartridge.

Hornady CX component bullets are available in the following configurations: .224-inch (50-grain),
6mm (80- and 90-grain), .257-inch (90-grain), 6.5mm (120- and 130-grain), .277-inch (100- and 130-grains), 7mm (139-, 150- and 160-grain), .308 (150-, 165-, 180- and 190-grain), .338-inch (185- and 225-grain), and .375 (250-grain).

Hornady Outfitter ammunition is available in the following cartridges:
.243 Winchester (80-grain CX), .257 Weatherby Magnum (90-grain CX), 6.5 Creedmoor (120-grain CX), 6.5mm PRC (130-grain CX), .270 Winchester (130-grain CX), .270 WSM (130-grain CX), 7mm Remington Magnum (150-grain CX), 7mm WSM (150-grain CX), 7mm PRC (160-grain CX), .308 Winchester 150- and 165-grain CX, .30-06 Springfield (150- and 180-grain CX), .300 WSM (180-grain CX), .300 Winchester Magnum (180-grain CX), .300 Weatherby Magnum (180-grain CX), .300 Remington Ultra Magnum (180-grain CX), .300 PRC (190-grain CX), .338 Winchester Magnum (225-grain CX), .375 Ruger (250-grain CX), and .375 H&H Magnum (250-grain CX).

SHOULD WE ALL make the switch over to copper alloy projectiles? Well, I feel that the exclusive use of copper bullets might be a bit hasty right now – unless, of course, you live in California or another area that mandates their use. But if I had a rifle/cartridge combination that I were fond of, I would want at least one load featuring a copper bullet that printed acceptable groups should things change quickly, or should you want to travel to hunt.
You could certainly do a lot worse than the Hornady CX; like the older GMX bullet, I have no complaints whatsoever with the design, and if the improvements made by Hornady equate to a boost in performance and shooter confidence, all the better. They hit hard, kill quickly and shoot accurately. What more could a hunter ask for?